20 EXPLANATION OF PLATES 6. 7. 



12, 13. Armour, supposed to be that of Megatherium.* 

 14 19. Armour of Dasypus and Chlamyphorus. 



Plate 6. V. I. p. 148. 



1. Sections of Teeth of Megatherium, illustrating the 



relative dispositions of the Ivory, Enamel, and Crusta 

 petrosa, or Coementum. (Original. Clift.) 



2. Posterior surface of a caudal vertebra of Megatherium, 



exhibiting enormous transverse processes. On its 

 lower margin are seen the articulating surfaces 

 which received the chevron bone ; the superior 

 spinous process is broken off. V. I. p. 151. (Sir 

 F. Chantrey. Original.^ 



Plate 7. V. I. p. 168. 



Ichthyosaurus platyodon from the Lias at Lyme Regis, 

 discovered by T. Hawkins, Esq. and deposited in the Bri- 

 tish Museum, together with alLthe other splendid fossil re- 

 mains that are engraved in his memoirs of Ichthyosauri 

 and Plesiosauri. This animal, though by no means full 

 grown, must have measured twenty-four feet in length. The 

 extremity of the tail, and left fore paddle, and some lost 



* Mr. Darwin has recently discovered the Remains of Mega- 

 therium along an extent of nearly six hundred miles, in a North and 

 South line, in the great sandy plains of the Pampas of Buenos Ayres, 

 accompanied by bones and Teeth of at least five other Quadrupeds. 

 He has also found that the Bones of this Animal are so often accom- 

 panied by those of the Mastodon angustidens, as to leave no doubt 

 that these two extinct species were contemporary. 



I learn from Professor Lichstenstein, that a fresh importation of 

 Bones of Megatherium, and bony armour has lately been sent to 

 Berlin from Buenos Ayres, and that there remains no room to doubt 

 that some portion of this armour appertained to the Megatherium. 



It appears very probable, from more recent discoveries, that 

 several other large and small animals, armed with a similar coat of 

 mail, were co-inhabitants of the same sandy regions with the Mega- 

 therium. 



